Emergency flotation device with chemical reaction chamber

Abstract

An inflatable flotation device having a reaction chamber with reactants that generate gas when mixed, said reactants being separated by a barrier assembly; an activating mechanism adapted to remove or puncture the barrier assembly such that said reactants mix; and an inflatable compartment fluidly connected to the reaction chamber by means of a pressure sensitive passageway, adapted to open only when the pressure of the gas in said reaction chamber exceeds a predetermined threshold. This ensures that most of the reactants are used up to generate gas before the gas enters the inflatable chamber, thus preventing scattering of the reactants. Some implementations have a reaction chamber without a barrier assembly, comprising reactants that generate gas when mixed with water and an activating mechanism adapted to expose the reactants to water. A variety of manual or automatic mechanisms may be employed to activate the reaction and inflate the device.

We claim: 
     
       1. An inflatable flotation device comprising:
 a reaction chamber comprising one or more reactants that generate gas when mixed with water; 
 a water inlet valve connecting the reaction chamber to an ambient water environment surrounding the device such that the ambient water surrounding the device fills the reaction chamber when the water inlet valve is open; 
 a sensor indicative of immersion in water for more than a predetermined time, and providing a signal to activate the inflation flotation device; and 
 an inflatable compartment fluidly connected to said reaction chamber by means of at least one pressure sensitive passageway comprising a one-way valve, a semi-permeable membrane or a tail adapted to enable uni-directional gas flow towards the inflatable compartment when the pressure of the gas in the reaction chamber exceeds a predetermined threshold, 
 wherein the predetermined threshold, at which the passageway opens, is that at which the reaction between the reactants and the water is complete, according to a predefined completion criterion, such that the reactants are kept within the reaction chamber until the reaction is complete according to the predefined completion criterion, and 
 wherein the predefined completion criterion at which the reaction between the reactants and the water is considered to be complete is at least one of: (i) 70% of the reaction, (ii) 80% of the reaction, (iii) 90% of the reaction, or (iv) 95% of the reaction. 
 
     
     
       2. An inflatable flotation device according to  claim 1 , wherein the at least one pressure sensitive passageway is further adapted to provide substantially preferential passage of the gas rather than the reactants. 
     
     
       3. An inflatable flotation device according to  claim 1 , wherein the water inlet valve is actuated by a manual actuating mechanism. 
     
     
       4. An inflatable flotation device according to  claim 1 , wherein the reaction chamber further comprises a water outlet valve, such that the reaction chamber can be emptied after use. 
     
     
       5. An inflatable flotation device according to  claim 1 , wherein the sensor is adapted to detect any one of vibration, depth, pressure or light. 
     
     
       6. An inflatable flotation device according to  claim 1 , wherein the reactants are solids. 
     
     
       7. An inflatable flotation device according to  claim 1 , wherein the at least one pressure sensitive passageway is either a semi-permeable membrane preferentially enabling passage of gases over liquids, or is sufficiently small that it allows substantially preferential passage of the gas rather than the reactants. 
     
     
       8. An inflatable flotation device according to  claim 1 , wherein at least one reactant is in a non-aqueous state. 
     
     
       9. An inflatable flotation device according to  claim 1 , wherein the reactants comprise a volume of less than 80 milliliters and generate a sufficient amount of gas for adequate inflation capabilities of the device. 
     
     
       10. An inflatable flotation device comprising:
 an inflatable compartment; 
 a blister pack assembly within the inflatable compartment, the blister pack assembly comprising a first set of volumes comprising a first reactant and at least a second volume comprising a second reactant, the reactants selected to generate a volume of gas when mixed, and the first set of volumes being separated from the at least second volume by at least one separation layer; 
 wherein, the at least one separation layer is adapted to be removed to enable a reaction to occur between the first and second reactants, such that the gas inflates the inflatable compartment. 
 
     
     
       11. An inflatable flotation device according to  claim 10  further comprising an inner reaction chamber containing the blister pack assembly within the inflatable compartment, such that the reaction chamber is fluidly connected to the inflatable compartment by means of at least one pressure sensitive passageway, adapted to open when the pressure of the gas in the reaction chamber exceeds a predetermined threshold. 
     
     
       12. An inflatable flotation device according to  claim 10  further comprising a water inlet valve connecting the inner reaction chamber to an ambient water environment of the device such that the reaction chamber can be filled from the ambient water surrounding the device when the water inlet valve is open. 
     
     
       13. An inflatable flotation device according to  claim 10 , wherein the separation layer is adapted to be actuated by a manual trigger. 
     
     
       14. An inflatable flotation device according to  claim 13 , wherein the manual trigger is at least one cord attached to the separation layer. 
     
     
       15. An inflatable flotation device according to  claim 10 , further comprising a sensor indicative of immersion in water for more than a predetermined time, and providing a signal to activate the inflation device. 
     
     
       16. An inflatable flotation device according to  claim 10 , wherein the first set of volumes comprises a first plurality of blisters of the blister pack and the at least second volume comprises a second plurality of blisters of the blister pack, such that when the at least one separation layer is removed, the reactants mix. 
     
     
       17. An inflatable flotation device comprising:
 a reaction chamber comprising reactants that generate gas when mixed, the reactants being separated by a barrier sheet; 
 a pointed element adapted to puncture the barrier sheet such that the reactants mix; and 
 at least one pressure sensitive element adapted to open when the pressure of the gas in the reaction chamber exceeds a predetermined threshold, the pressure sensitive element being disposed between the reaction chamber and a flotation compartment inflatable by the gas.